#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
	int i = 0;
	double num[5] = { 0 }, average = 0,sum = 0;
	for (i = 0; i < 5; i++)
		scanf("%lf.2", &num[i]);
	for (i = 0; i < 5; i++)
		sum += num[i];
	printf("%.2lf\n",average = sum / 5);
}







